this is the opinion cal for a musician. >> reporter: ll cool j ought to know. the hip-hop superstar will host tonight's primetime grammy nomination special as he has for each of the past five years on cbs. >> i've been doing this since the grammy nominations, since the inception of the grammy nominations and it's been fun every year. it's been different every year. i think music fans are music fans. you come to nashville people appreciate good music. >> reporter: ll cool j will co-host with taylor swift to announce this year's nominees. the stage will be in nashville america's country music capital but the hour long special will showcase the best of all popular music. we got a back stage tour in the arena and caught nashville country music star luke bryan doing a sound check. >> truly amazing to be a part of this night and part of the grammy nomination show and with hopes to of guesting a grammy nomination and i want seems like a grammy nomination never has been in my realm of, i guess, i guess expectations to get that would be just truly out of the park. ♪ >